utils

type Authorizer struct {
	sync.Mutex // bind.TransactOpts is not thread safe
	*bind.TransactOpts
}

type Blockchain interface {
	// CodeAt returns the code of the given account. This is needed to differentiate
	// between contract internal errors and the local chain being out of sync.
	CodeAt(ctx context.Context, contract common.Address, blockNumber *big.Int) ([]byte, error)
	// ContractCall executes an Ethereum contract call with the specified data as the
	// input.
	CallContract(ctx context.Context, call ethereum.CallMsg, blockNumber *big.Int) ([]byte, error)
	// PendingCodeAt returns the code of the given account in the pending state.
	PendingCodeAt(ctx context.Context, contract common.Address) ([]byte, error)
	// PendingCallContract executes an Ethereum contract call against the pending state.
	PendingCallContract(ctx context.Context, call ethereum.CallMsg) ([]byte, error)
	// PendingNonceAt retrieves the current pending nonce associated with an account.
	PendingNonceAt(ctx context.Context, account common.Address) (uint64, error)
	// SuggestGasPrice retrieves the currently suggested gas price to allow a timely
	// execution of a transaction.
	SuggestGasPrice(ctx context.Context) (*big.Int, error)
	// EstimateGas tries to estimate the gas needed to execute a specific
	// transaction based on the current pending state of the backend blockchain.
	// There is no guarantee that this is the true gas limit requirement as other
	// transactions may be added or removed by miners, but it should provide a basis
	// for setting a reasonable default.
	EstimateGas(ctx context.Context, call ethereum.CallMsg) (gas uint64, err error)
	// SendTransaction injects the transaction into the pending pool for execution.
	SendTransaction(ctx context.Context, tx *types.Transaction) error
	// FilterLogs executes a log filter operation, blocking during execution and
	// returning all the results in one batch.
	//
	// TODO(karalabe): Deprecate when the subscription one can return past data too.
	FilterLogs(ctx context.Context, query ethereum.FilterQuery) ([]types.Log, error)
	// SubscribeFilterLogs creates a background log filtering operation, returning
	// a subscription immediately, which can be used to stream the found events.
	SubscribeFilterLogs(ctx context.Context, query ethereum.FilterQuery, ch chan<- types.Log) (ethereum.Subscription, error)
	TransactionReceipt(ctx context.Context, txHash common.Hash) (*types.Receipt, error)
}